Self-winding watch impulse weight assembly



)v 1951 E. H. WILKENING 2,551,194

SELF-WINDING WATCH IMPULSE WEIGHT ASSEMBLY Filed D'ec. 6, 1948 2 Sheets-Sheet 1 r V JNVENTOR.

IdWMHWZZ/l'fllh y 1951 E. H. WILKENING SELF-WINDING WATCH IMPULSE WEIGHT ASSEMBLY 2 SheetvSheet 2 Filed Dec. 6, 1948 enz'ny,

Patented May 1, 1951 SELF-WINDING WATCH INIPULSE WEIGHT ASSEMBLY Edward H. Wilkening, Elgin, Ill., assignor to Elgin National Watch Company, Elgin, 111., a corporation of Illinois Application December 6, 1948, Serial No. 63,713

2 Claims. 1

This invention is concerned with improvements in the construction of self-winding watches which have inertia or impulse weights for producing a winding action upon the mainspring; and is more particularly addressed to the construction and arrangement of such impulse systems.

A feature of the invention is the provision of parts and arrangement of such a winding system, in which the weight has a limited arcuate movement about the general axis of the watch mechanism and has its mass located at least in part in the same radial plane as parts of the going movement of the watch itself, and in which the parts of the impulse winding structure can be removed without dismounting the parts of the going movement of the watch.

Another feature of the invention is the provision of an impulse weight arrangement for a self-winding watch, in which the mounting sector may be selected of one material, and the impulse weight of another material, and. these parts held fixedly together during their operation.

A further feature of the invention is the provision of a structure including a supporting sector and a weight in which the parts are detachably held together but which when in secured position are free of shake or relative movement.

With these and other features in View, as will appear in the course of the following specification and claims, an illustrative form of practicing the invention is shown on the accompanying drawings, in which:

Fig. 1 is a view, on an enlarged scale, of a watch movement removed from its case, and having the self-winding structure of this invention applied thereto.

Fig. 2 is a partial sectional view taken on planes represented by the lines 2-2 of Fig. l, on a larger scale.

Fig. 3 is a view showing the layout of the impulse sector, on a larger scale.

Fig. 4 is a corresponding view on the scale of Fig. 1, with parts broken away, showing the impulse weight.

Fig. 5 is a cross-sectional View substantially on line 55 of Fig. 2.

In these drawings, the watch movement has the usual rear plate or cook construction for supporting the rear ends of the staves and the like, including the members It) and H. The member I0 extends beyond the center axis of the watch movement and carries (Fig. 2) a jewel bearing [2 for the staff l3 of a sweep-second hand employed in the illustrated watch movement. Since the particular construction of the watch movement itself is not a part of the present invention, no further detail of it is set out in the drawing or in this description, except that the wind ratchet I5 is mounted on a shaft I l and thus in part supported by plate II; and the winding of this ratchet l5 acts through a train and accomplishes the winding of the mainspring in the barrel B supported in part by the barrel bridge 9, and the amount of winding produced by such motion is then maintained by the action of the holding pawl l6 pivotally supported by plate II, and urged into its engaging position by the pawl spring H.

The structure for moving the ratchet I5 includes the winding sector 20 which rocks about the axis of shaft I4 and has circular rack teeth 2| in mesh with the rack teeth 22 of the impulse weight sector 23. The winding sector 28 carries a pivot screw 25 on which is mounted the pawl 26, urged into engagement with the ratchet l5 by the pawl spring 21'. Thus, as the winding sector 20 moves in a clockwise direction in Fig. 1, the pawl 26 causes the ratchet E5 to turn in the direction for winding the mainspring, the ratchet [5 being engaged, tooth by tooth, by the retaining pawl l6. During counterclockwise movement of the winding sector 20, the pawl 26 slips over the teeth of the ratchet IE, but the latter remains held by its pawl 16. Q

The impulse weight sector 23 is supported (Fig. 2) on a short arbor 30 which has its ends mounted in the bearings 3| carried respectively by the sub-plate 32 secured to the plate It), and by the bridge piece 33 carried in spaced relation from plate II]. It will be noted that the axis of the arbor 30 is shown as coincident with the general central axis of the watch movement and of the sweep-second staif I 3.

The impulse weight sector 23 (Fig. 3) has parts 35 of its periphery concentric with its axis, while another part 36 is eccentric thereto, being illustrated as formed by a circular are having its center 31 located between the axis of the sector and its peripheral edge, so that the peripheral portion 36 extends radially beyond the portions 35. The impulse weight sector 23 has a hole 48 on the radial line 38 from the axis through the center-point 31, and thus located essentially opposite the mid-point of the peripheral portion 36. This hole 40 is illustrated as having a straight outer edge 4|, and a semicircular inner edge 42, these edges being joined by short straight side edges 43.

The impulse weight (Figs. 2 and 4) is arcuate in shape, and is illustrated as extending through 180 degrees about the general axis ol the watch movement. It is of essentially uniform cross-section from end to end, in having a radially inward face M which is clylindrical, and an outer face 52 which is concentrically cylindrical. The upper and lower faces (Fig. 2) are illustrated as radial, but it is preferred to have a slight chamier or bevel on the outer part oi the upper face, that is, at the rear part of this structure as it is present in a watch.

A notch 54 is formed in the radially inward face 5| (Fig. 2) of the impulse weight, near the top thereof as shown in Fig. 2, the bottom of this notch being curved (Fig. 4) to correspond to the shape of the peripheral portion or the impulse weight sector. Adjacent the center of length of this notch a radial hole 55 is provided, with a counterbore 56 at the outer face 52 of the impulse weight, for receiving the locking screw 53. A counterbore hole is provided at the inner surface 5! or the impulse weight, being of a greater diameter than the width of the hole tlil between the side edges as.

A locking nut 65 (Fig. 5) is of generally circular outline, and of a size slightly smaller than the diameter of the counterbored hole Eli. Two right-angled notches are cut into the edge of this nut, to provide a tongue w ch can extend into the hole as of the impulse weight sector 23 to be guided thereby and prevented from turning about the axis of the nut. The internal thread in the locking nut 65 is relatively large, compared to the external thread of the screw 5-8, so that there is looseness and permissive rocking motion of these parts: in practice, the tolerances for which practice are proper.

In assembling the impulse sector with its weight, the sector has its peripheral portion 33 engaged in the notch t t, and the parts are moved slightly back and forth in the arcuate direction, while the locking nut is engaged with its tongue G6 in the hole while its body is in the ccunterbored hole as and thus opposite the hole 55. At this time, 2, the peripheral portion 36 of the sector is alight pressure fit the notch 5 and therewith these parts can slide, under pressure, with respect to one aanother, but cannot have a relative rocking motion about an axis at right angles to the plane of Fig. 2. The screw 58 is now engaged with the locking nut and is tightened. The locking nut 65 now acts a lever, with a fulcrum against thewall at the bottom oi counterbored hole 59, in Fig. 2, and with pressure being applied atthe middle of its length by the screw 58, so that its tongue '55 fits against the edge ll of the hole ll], and draws the parts tightly together by afo 'esaid sliding motion. In turn, these small parts are tightened, a minor strain and minor deformation of the locking nut occurs, so that the screw till cannot become loosened accidentally. However, at any time of damage to the sector or the weight, the parts can'be separated by forcible unscrewing of the screw 53.

This two-part construction permits the making of the impulse weight sector 23 or" a material of high strength, such as stainless steel, and the making or" the impulse weight itself of a high density material such as a tungsten alloy which may have a density as high as 6.614 pound per cubic inch, in comparison to a density of 6.309 pound per cubic inch for leaded brass. Stainless steel and the tungsten alloy, however, have the 4 diificulties that they do not permit easy fusing, soldering, brazing or welding methods, except under conditions which produce deformation of parts or discoloration; wherewith refinishing becomes necessary after the joining operation.

On the other hand, even though the parts for a self-winding watch are individually small, the loads considered in terms of pounds per square inch, may be high. In particular, when the im-- pulse weight 5i (Fig. 1) approaches the end of its stroke, in response to a movement of the arm of the wearer of the watch, and therewith encounters the buffer spring ill at that end, couples of forces are established at various parts of the winding system, along with a tendency toward relative peripheral slippage of the impulse sector and the impulse weight. The present arrangement, in which the tongue 66 of the looking nut is closely received between the edges 43 of the hole ill and therewith prevented from turning about its own axis, and wherein the screw 58 cooperates with this nut in providing a main,- tained pressure between the parts, there is a very rigid fastening and securing of the pieces, so that they become essentially a unit and operate by the reciprocation about the common axis.

It is obvious that the specific form illustrated is not restrictive, and that the invention may be practiced in many ways within the scope of the appended claims.

What is claimed is:

1. An impulse winding assembly for a watch having supporting members, a mainspring, and means for winding the same including a winding sector the combination therewith of an impulse sector carried upon the supporting members and in driving relation with said winding sector, said impulse sector having a hole near its periphery, an impulse weight having a radially inward notch for receiving the peripheral edge of the impulse sector, a nut having a part guided in said hole and having a part engaged with the outward wall thereof, said nut also having another part engaged with the impulse weight, and a screw mounted on the impulse weight and engaged with the nut between said engaged parts whereby to hold the impulse sector andweight together.

2. An impulse winding assembly for a watch having supporting members, a mainspring and a driving train mounted on said supporting members, the combination therewith of a bridge piece detachably secured to said supporting member, a winding ratchet rotatably mounted on said bridge piece and on a said supporting member and connected for winding said mainspring, a detaining pawl engaged with said ratchet, a winding sector r ckably mounted coaxially with said ratchet, a driving pawl mounted on said windingsector and engaging said ratchet, an impulse sector rockably mounted on and between said bridge piece and a said supporting member, said sectors being interengaged whereby movement or the impulse sector is transmitted to the winding sector, said impulse sector being flat and extendins essentially in a radial plane of its axis of rocking and having an outwardly projecting lug at its periphery, an impulse weight ofarcuate form and essentially uniform cross-section, said weight having a groove of limited peripheral extent on its inner face essentially at its center of gravity for closely receiving said lug, and means for detachably securing said impulse sector and weight together, saidbridge piece being separable from said supporting members whereby said sectors and weights can be removed independently of said train.

EDWARD H. WILKENING.

REFERENCES CITED The following references are of record in the file of this patent:

Number Number Switzerland Dec. 16, 1933 

